Due to thermodynamics, the efficiency of an internal combustion engine increases with the combustion temperature. Therefore, for gas turbines used in numerous variants in aircraft, but also in other vehicles and in stationary applications, one aspires to ever higher temperatures in the combustion chamber(s). In the high-pressure section of the turbine directly downstream of the combustion chamber(s), all open surfaces of guide vanes and rotor blades and other exposed components are subject to these high temperatures. To be able to operate a turbine at a highest possible temperature, the components, in particular the blades, which are exposed to the hot gas stream, are cooled by interior cooling channels and by a film cooling.
Integrally bladed rotor disks have been developed for compressors that are coupled upstream of the combustion chamber and are, therefore, not subject to the hot combustion temperatures. Since a number of disadvantages are entailed in manufacturing an integrally bladed rotor disk from one piece, the rotor blades are normally manufactured individually and then joined in an integral metallurgical bond to a disk element by friction welding or some other method. The U.S. Patent Application 2005/0232780 A1 describes an integrally bladed rotor disk for a turbine, where entry orifices of the inner cooling channels are each configured on the shaft of a blade. Platforms configured in each case between the shaft and the blade can be welded to one another circumferentially. Alternatively, seal strips are configured between mutually opposing platform edges.
The rotor disk described in U.S. Patent Application 2005/0232780 A1 has the inherent disadvantage that cooling air can flow through between the shafts of the rotor blades, from the high-pressure side to the low-pressure side of the rotor disk. Due to reasons related to production engineering, in certain manufacturing processes, it is not possible or not easily possible to have circumferentially measured spacing intervals between the shafts whose widths are below a minimum value. Since power is required to compress cooling air in the compressor that is then supplied to the turbine, every unwanted outflow of cooling air negatively affects power efficiency and is, therefore, to be avoided to the extent possible.